Microdroplet Detection of Precision Dispensing for Miniature Parts Assembly Technology

Abstract

Microdroplet detection is the key for precision dispensing technology, which is widely applied in precise assembly of miniature parts, microelectronics packaging and biological tests. In order to measure droplet in micro scale for different working conditions, In this paper, an on-demand detection method--which is composed of statistical weighing detection to measure batch dispensing quality for large-scale production, real-time visual detection to measure droplet area and position accuracy for flexible production as well as pressing-plate method to measure nanoliter volume for single microdroplet detection--is presented. An automatic dispensing system to generate microdroplets is developed and the procedure of online detection based on machine vision of this dispensing system is introduced. Experimental results show that dispensing standard deviations measured by on-demand detection are 2.5 µg, 2.8 nl and 0.013 mm2 for weighing method, real-time detection and pressing-plate method, respectively. The results also prove that the pressing-plate method can measure single micro droplet of 10 nl.